The antibiotic pleuromutilin was isolated in 1951 by Kavanagh et al. [Proc. Natl. Acad. Soc. 37, 570-574 (1951)]. The structure of pleuromutilin was later shown to be ##STR1## Alkaline hydrolysis of pleuromutilin gives a compound which is known as mutilin. Mutilin has the following structure: ##STR2## A great number of pleuromutilin derivatives have been prepared [Swiss Pat. No. 572,894 (Derwent No. 26553X); Netherlands Pat. No. 69,11083 (Derwent No. 40,642); Knauseder et al., U.S. Pat. No. 3,716,579; Egger et al., U.S. Pat. No. 3,919,290; Brandl et al., U.S. Pat. No. 3,949,079; Reidl, U.S. Pat. No. 3,979,423; Baughn et al., U.S. Pat. No. 3,987,194; Egger et al., U.S. Pat. No. 4,032,530; K. Riedl, "Studies on Pleuromutilin and Some of Its Derivatives," J. Antibiotics 29, 132-139 (1976); H. Egger and H. Reinshagen, "New Pleuromutilin Derivatives with Enhanced Antimicrobial Activity. I. Synthesis," J. Antibiotics 29, 915-922 (1976) and "II. Structure-Activity Correlations," ibid., 923-927 (1976); F. Knauseder and E. Brandl, "Pleuromutilins: Fermentation, Structure and Biosynthesis," J. Antibiotics 29, 125-131 (1976); J. Drews et al., "Antimicrobial Activities of 81.723 hfu, a New Pleuromutilin Derivative," Antimicrob. Agents and Chemotherapy 7, 507-516 (1975)].
We have discovered two antibiotics which are new members of the pleuromutilin family of antibiotics. In addition, we have discovered a new method of making pleuromutilin.